"The occupants of the WFP vehicles -- including WFP staff and a visiting journalist -- are all safe, although two private security guards escorting the team were slightly wounded," Almagro told Xinhua.

"We are investigating the incident, including whether or not the convoy was the intended target," Almagro added.

She said the convoy was returning from KM-13, an area on the outskirts of Mogadishu where WFP is providing life-saving emergency food and nutritional assistance to people affected by drought.

Somali militant group Al-Shabaab said in a statement posted on its website on Sunday they used a remote controlled landmine to attack the WFP convoy and its escorting soldiers.

The insurgents, who have upped their attacks since new Somali President Mohamed Abdullahi Mohamed was elected into office, claimed that the explosion struck through one of the vehicles and inflicted casualties on WFP staff members.

Nearly 3 million people in Somalia are in urgent need of food assistance due to severe drought, but humanitarian workers there are increasingly targeted by the Al-Shabaab that is fighting to topple the Somali government .

"It is vital that relief agencies are able to safely reach drought-affected communities to provide lifesaving humanitarian assistance as this drought crisis worsens," Almagro said.

The humanitarian community has said the volatile security situation continues to impact on civilian lives and create a challenging environment for the delivery of humanitarian assistance.